Department of Anaesthesia, Affiliated Hospital of North Sichuan Medical College, Nanchong, China.
Medical College, Jinan University, Guangzhou, China.
Basic Clin Pharmacol Toxicol. 2022 Nov;131(5):364-371. doi: 10.1111/bcpt.13777. Epub 2022 Aug 16.
Dexmedetomidine is commonly used in hysteroscopy surgery due to its analgesia and sedation without respiratory depression. Many studies have shown that dexmedetomidine can reduce the consumption of sevoflurane. However, the optimal end-tidal concentration of sevoflurane when it is co-administered with dexmedetomidine has not been established. The primary purpose of this study was to investigate the minimal alveolar concentration (MAC) of sevoflurane for cervical dilatation combined with different doses of dexmedetomidine in patients with hysteroscopy surgery.
One-hundred patients undergoing hysteroscopy surgery were enrolled in this clinical trial. All the patients were randomly assigned into four groups (C, D , D , D ) and received a loading dose of dexmedetomidine (0, 0.6, 0.8 and 1.0 μg/kg) over 10 min before anaesthesia induction, respectively. Anaesthesia was induced in each patient with 5% sevoflurane in 100% oxygen via a facemask. A laryngeal mask (LMA) was inserted when the patient had lost consciousness and the BIS value decreased below 40. The response to cervical dilatation stimulus (movement vs non-movement) by the insert of hysteroscope was recorded. The MAC of sevoflurane was measured by up and down sequential method of Dixon and Mood and centred isotonic regression analysis.
The calculated MAC of sevoflurane using up-and-down method of Dixon and Mood in patients with hysteroscopy surgery was (1.90 ± 0.13)%, (1.23 ± 0.16)%, (1.03 ± 0.10)% and (0.93 ± 0.08)% in groups C, D , D and D , respectively.
The administration of dexmedetomidine can significantly decrease the MAC of sevoflurane for hysteroscopy surgery. However, a ceiling effect of the reduction was observed when the dose of dexmedetomidine was higher than 0.8 μg/kg.
右美托咪定由于具有镇痛和镇静作用而无呼吸抑制作用，常用于宫腔镜手术。许多研究表明，右美托咪定可以减少七氟醚的用量。然而，右美托咪定与七氟醚联合使用时的最佳呼气末浓度尚未确定。本研究的主要目的是探讨宫腔镜手术中不同剂量右美托咪定复合七氟醚的肺泡最低有效浓度（MAC）。
本临床试验纳入 100 例行宫腔镜手术的患者。所有患者均随机分为四组（C、D 、D 、D ），分别在麻醉诱导前 10min 内给予右美托咪定负荷剂量（0、0.6、0.8和 1.0μg/kg）。所有患者均通过面罩给予 5%七氟醚 100%氧气诱导麻醉。当患者意识丧失且 BIS 值降至 40 以下时，插入喉罩（LMA）。记录插入宫腔镜时对宫颈扩张刺激的反应（运动与非运动）。采用 Dixon 和 Mood 上下序贯法和中心等张回归分析测定七氟醚的 MAC。
用 Dixon 和 Mood 上下序贯法计算宫腔镜手术患者的七氟醚 MAC 值分别为 C、D 、D 、D 组 1.90±0.13%、1.23±0.16%、1.03±0.10%和 0.93±0.08%。
右美托咪定的给药可显著降低宫腔镜手术中七氟醚的 MAC。然而，当右美托咪定剂量高于 0.8μg/kg 时，观察到降低的上限效应。
